Secondary Causes of Hypertension Flashcards
primary hyperaldosteronism is from
an adrenal adenoma or bilateral adrenal hyperplasia that secretes excess aldosterone see hypertension and hypokalemia and metabolic alkalosis.
why do we not see hypernatremia with primary hyperaldostonism if excess aldosterone should theoretically increase Na, lower K and increase H2O
There’s no hypernatremia or edema despite increased renal absorption because of aldosterone escape where increased HTN results in increased blood volume to kidneys so there’s higher GFR and atrial natriuretic peptide so increased Na excretion and no edema that forms
initial evaluation for primary hyperaldosteronism is
morning plasma aldosterone concentration (PAC) to plasma renin activity (PRA) ratio.
what is an abnormal PAC/PRA Plasma aldosterone conc / plasma renin activity ratio that would suggest a primary hyperaldosteronism?
PAC/PRA ratio >20 with plasma aldosterone >15 ng/dl This isn’t it though. needs a confirmation test
if there’s a positive screening test, what’s the confirmatory test for primary hyperaldosteronism?
needs an aldosterone suppression test.
give IV or oral sodium load and measure aldosterone level later and see if it’s suppressed.
If not suppressed then it’s an aldosteronism excess.
This doesn’t rule out if it’s bilateral metaplasia or adrenal adenoma
once primary hyperaldosteronism is confirmed need to figure out if it’s a adrenal adenoma or bilateral adrenal metaplasia and so need
CT imaging and look for adrenal gland abnormalities. NOTE CT scan sucks at picking up small tumors and so needs to get a adenal venous sampling
when do you get adrenal venous sampling?
when you’ve confirmed that you have primary hyperaldosteronism but CT scan doesn’t tell you if it’s adrenal adenoma or bilateral adrenal hyperplasia
treatment of primary hyperaldosteronism
surgery if it’s a single adrenal adenoma medical therapy with spironolactone or eplerone if its bilateral adrenal hyperplasia
what is the pathophysiology for primary hyperaldosteronism and aldosterone escape?
if pt has recurrent flash pulmonary edema and atherosclerotic dx and severe hypertension, should think of
renovascular dx due to bilateral renal artery stenosis.
Causes of secondary hyperaldosteronism
When the PAC/PRA is not greater than 20
features concerning for Renal artery stenosis
atherosclerosis in hx, rapid onset of HTN in pts >55 yrs old with risk factors for atherosclerosis (smoking).
Can also see abrupt increase in Cr after being on ACE, recurrent flash pulm edema, abdominal bruits and asymmetrical renal size on imaging.
clinical clues to renovascular disease (chart)
treatment for bilateral renal artery stenosis
needs ACE i or ARB. no longer contraindicated but most pts will experience a small decline in glomerular filtration rate
HTN in RAS is caused by RAAS which leads to sodium retention and volume expansion. So the ACEi + diuretic will help with prevention of CKD, decrease risk for MI, stroke, decreased mortality.
It’s as effective as angioplasty in pts
in renal artery stenosis who gets stenting?
people who fail optimal medical therapy (refractory HTN, inability to tolerate medications, progressive renal insufficiency)
what causes plasma renin levels to be low
what about high?
low:
in primary hyperaldosteronism - high aldosterone and so not trying to hold onto water
suppression of antihypertensives- the meds suppress levels
high sodium diet or bilateral renal artery dx - already has high salt water retention so trying not to hold onto water b/c already has HTN
Can be high
if theres renal renovascular hypertension.
Pickering Syndrome
bilateral renal artery stenosis pts can have flash pulmonary edema despite normal LV EF.
how to evaluate for renal artery stenosis?
renal doppler ultrasound and CT or MR angiography
HTN factors that should make one consider renovascular dx?
resistant HTN (uncontrolled despite 3 drug regimen)
malignant HTN (w/ end organ damage)
Onset of severe HTN>180/120 after age 65
severe HTN with diffuse atherosclerosis
recurrent flash pulmonary edema with severe HTN
physical exam: asymmetric renal size >1.5 cm, abdominal bruit
lab results: unexplained rise in Cr >30% after starting an ACEi or ARB
imaging results: unexplained atrophic kidney
renovascular dx
when should spirolactone and eplerenone be stopped prior to screening?
Stop 6 weeks prior to screening for primary hyperaldosteronism (aldosterone/renin) because these can affect interpretation of labs.
what to do if there’s an incidental adrenloma?
fibromuscular dysplasia is
see twisting and beading of the renal artery. presents with HTN in young female
CT angiography or ultrasound with dopplers is ok to use.
management: ACEi or ARB o r angioplasty
hypertension, metabolic alkalosis, hypokalemia
think: primary hyperaldosteronism.
testing: stop diuretics to assure euvolumia
get PAC/PRA ratio >20 is positive
confirmatory testing: oral or IV salt loading and fludrocortisone suppresion and captopril challenge tests.
